Article View: comp.arch
Article #12663Re: Floating point accuracy
From: Henry Spencer
Date: Tue, 11 Nov 1986 19:40
Date: Tue, 11 Nov 1986 19:40
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> The mechanism was to add a random number in the range 0 to 1 in the last
> digit and then truncate. This gives better RMS error than most other rounding
> schemes. It also has the advantage that numerically unstable programs are
> easy to detect (they give wildly differing results on each run).
> Sadly I believe this has never been implemented...
The IBM 7030, aka Stretch, had a random-rounding mode, although possibly
using a somewhat simpler method. The idea was to run your program twice,
once with normal rounding and once with random rounding, and see how the
results differed.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,decvax,pyramid}!utzoo!henry
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: comp.arch Subject: Re: Floating point accuracy Message-ID: <7313@utzoo.UUCP> Date: Tue, 11-Nov-86 14:40:29 EST Article-I.D.: utzoo.7313 Posted: Tue Nov 11 14:40:29 1986 Date-Received: Tue, 11-Nov-86 14:40:29 EST References: <340@euroies.UUCP> <1989@videovax.UUCP>, <267@bath63.UUCP> Organization: U of Toronto Zoology Lines: 13